1. Technical Field
The present invention relates to magnetic tape heads. More specifically, the present invention relates to a method and apparatus for reducing the complexity of tape heads while accommodating an increased number of data tracks on record media.
2. Description of Related Art
Advanced record media (tapes) store data on multiple data tracks, which run parallel to each other over the length of the tape. However, there is an inherent problem associated with independent data tracks. As the tape moves past the tape head, lateral drift of the tape could result in the head reading or writing on the wrong data track. This would obviously degrade the quality of data storage and retrieval. To ensure that the tape heads are accurately positioned relative to the tape, dedicated servo tracks are usually recorded on the tape parallel to the data tracks. These servo tracks are read by servo readers on the tape head. The servo readers then signal mechanisms within the tape drive that are capable of adjusting the tape head in order to maintain proper alignment with the data tracks. The standard configuration in a three-module read/write/read head is to place servo readers symmetrically about the write module of the tape head. This placement allows the head to read or write in both directions of tape motion in a given position.
Increasing the amount of data on a fixed area of tape can be accomplished either by increasing the linear recording density or increasing the number of data tracks on tape. In the latter case, the data track width is reduced to accommodate the larger number of data tracks on a fixed width of tape. However, the larger number of data tracks requires an increase in the number of possible head positions relative to the tape, in order to accurately read and write the additional data tracks. For example, a 16-track head would require nine separate servo positions to write and read 144 tracks but 18 positions to write 288 tracks on the same tape. To accommodate the extra tracks, typical systems either increase the number of servo tracks on tape or increase the number of servo readers on the head.
However, both options have their drawbacks. If the number of servo tracks on the tape is increased, there will be less space available for data tracks. If the number of servo readers is increased, the tape heads will become more complex, which presents problems for manufacturing, especially as the size of the tape heads is reduced.
Therefore, a tape head design that can efficiently accommodate increased information storage, without increasing complexity is desirable.
The present invention provides a magnetic tape head assembly comprised of read and write elements and servo readers placed asymmetrically about the center of the head taken perpendicular to the direction of tape motion. The tape head is capable of reading and writing in two directions of tape motion.